Listen to Deep Purple online radio. Deep Purple are a British rock band formed in Hertford in 1968. They are considered to be among the pioneers of heavy metal and modern hard rock, although their musical approach changed over the years. Originally formed as progressive rock band, the band's sound shifted to hard rock in 1970. They were listed in the 1975 Guinness Book of World Records as "the globe's loudest band" for a 1972 concert at London's Rainbow Theatre, and have sold over 100 million albums worldwide, including 17.5 milli